1. Field of the Invention
This invention relates to quality control in the field of semiconductor wafer oriented manufacturing of integrated circuits.
2. Description of the Related Art
Integrated circuit manufacturing and testing requires a high degree of quality control. An integrated circuit (IC) is a miniature electric circuit composed of hundreds to tens of millions of discrete electronic circuit elements (e.g., transistors, resistors, capacitors, or inductors). Multiple ICs are manufactured, or formed, on semiconductor wafers (also known as integrated circuit wafers), through a series of oxidations, implants, controlled deposition of materials, and selective removal of materials. Manufacturing integrated circuit wafers typically requires upwards of between two hundred and four hundred discrete manufacturing steps. One discrete manufacturing step is the controlled deposition of Polyimide. Polyimide is a plastic coating, which is typically used as a xe2x80x9cstress buffer.xe2x80x9d Generally, Polyimide is the last (or nearly last) coating applied to each semiconductor wafer. Once the manufacturing process is complete (e.g., the Polyimide is deposited), a wafer upon which the Polyimide has been deposited will be divided into individual die (or chips). Each functional die will thereafter typically be sold as an individual IC.
The Polyimide protects the die produced from the wafer from thermal expansion, so it is often described as a thermal stress buffer. In addition, Polyimide also works as a cushion between the chip and the packaging (a black epoxy that usually encapsulates the chip). For example, a chip, during its use, typically heats up and cools down (due to the dissipation of electrical energy as heat) causing the chip to thermally expand and contract. Polyimide works to allow chips coated with Polyimide to thermally expand and contract without sustaining excessive damage. Polyimide also works to ensure that chips coated with Polyimide don""t become damaged by rubbing up against the chip""s packaging in the process of such chips"" thermal expansion and contraction. Polyimide thus constitutes a very important part of most integrated circuits.
Polyimide is relatively expensive substance. For example, in the years 1999 and 2000, Polyimide""s cost has averaged about $500 per kilogram. Insofar as, in the related art, each standard wafer requires approximately 3.0 grams of Polyimide per 6 inch wafer, and each facility generally processes about 20,000 Polyimide requiring wafers per month, it is apparent that costs associated with Polyimide are relatively significant.
The inventors named herein has invented a system which allows for reduced consumption of Polyimide per semiconductor wafer. In one embodiment, the system includes but is not limited to a Polyimide solvent dispensing nozzle proximate to a Polyimide dispensing nozzle. In one embodiment, the Polyimide solvent dispensing nozzle proximate to a Polyimide dispensing nozzle further includes but is not limited to the Polyimide solvent dispensing nozzle coupled with a bracket assembly adjustable in three dimensions. In one embodiment, the Polyimide solvent dispensing nozzle coupled with a bracket assembly adjustable in three dimensions further includes but is not limited to a bracket assembly adjustable in an x-axis direction, y-axis direction, and z-axis direction. In one embodiment, the Polyimide solvent dispensing nozzle proximate to a Polyimide dispensing nozzle further includes but is not limited to the Polyimide solvent dispensing nozzle mounted on an arm holding the Polyimide dispensing nozzle. In one embodiment, the Polyimide solvent dispensing nozzle mounted on an arm holding the Polyimide dispensing nozzle further includes but is not limited to the Polyimide solvent dispensing nozzle mounted with a bracket assembly adjustable such that the Polyimide solvent dispensing nozzle is centerable over a wafer holder. In one embodiment, the Polyimide solvent dispensing nozzle is fed by a Polyimide solvent reservoir. In one embodiment, at least one dispense/suckback valve is interposed between the Polyimide solvent dispensing nozzle and the Polyimide solvent reservoir. In one embodiment, at least one air operated valve is operably connected with interposed between the Polyimide solvent dispensing nozzle and the Polyimide solvent reservoir.
The foregoing is a summary and thus contains, by necessity, simplifications, generalizations and omissions of detail; consequently, those skilled in the art will appreciate that the summary is illustrative only and is not intended to be in any way limiting. Other aspects, inventive features, and advantages of the present invention, as defined solely by the claims, will become apparent in the non-limiting detailed description set forth below.
The present invention may be better understood, and its numerous objects, features, and advantages made apparent to those skilled in the art by referencing the accompanying drawings.
FIG. 1 shows an index of FIGS. 2-11.
FIG. 2 depicts solvent dispensing nozzle bracket 200 and solvent dispensing nozzle block 202 (which collectively can be referred to as a xe2x80x9cbracket assembly) and solvent dispensing line 204.
FIG. 3 illustrates that arm 214 has been positioned such that solvent dispensing nozzle 300 is roughly centered over semiconductor wafer 302 residing upon wafer holder 210 internal to cup 212.
FIG. 4 shows a perspective view of an embodiment of a solvent chemical supply system as implemented on a Dainippon Screen 623 coater.
FIG. 5 illustrates a perspective view of the underside of the portion of the Dainippon Screen 623 which underlies the portion of arm 214 of FIG. 2 and 3 where solvent dispensing line 204 passes internal to the Dainippon Screen 623 coater.
FIG. 6 illustrates piping diagram 600 of the embodiments described above in relation to FIGS. 1-5.
FIG. 7 depicts a parts list associated with numbered items in FIG. 6.
FIG. 8 shows various views of solvent dispensing nozzle bracket assembly 800 consisting of solvent dispensing nozzle block 202 and solvent dispensing nozzle bracket 200.
FIG. 9 illustrates a manufacturing drawing for an embodiment of solvent dispensing nozzle bracket 200 and solvent dispensing nozzle block 202.
FIG. 10 depicts a drawing of a NMP pre-wet valve mounting bracket manufacturing drawing.
FIG. 11 shows a manufacturing drawing for solvent drain 306 illustrated and described in relation to FIG. 3.
FIG. 12A depicts screen prints taken from the Dainippon Screen 623 coater of (1) recipe 1200 containing a recipe which is used to control the dispensing of 1.3 grams of Polyimide from an unmodified Dainippon 623 coater, and (2) recipe 1250 containing a recipe which is used, in one embodiment, with the modified Dainippon Screen 623 system in order to control the both the dispensing of the Polyimide solvent (NMP) and the subsequent dispensing of 1.3 grams of Polyimide.
FIG. 12B shows key 1204, which explains to what the various entries in recipes 1200 and 1250 refer.
FIG. 13 shows screen prints taken from the Dainippon Screen 623 coater of (1) recipe 1300 containing a recipe which is used to control the dispensing of 1.15 grams of Polyimide from an unmodified Dainippon 623 coater machine, and (2) recipe 1350 containing a recipe which is used, in one embodiment, with the modified Dainippon 623 coater machine system in order to control the both the dispensing of the Polyimide solvent (NMP) and the subsequent dispensing of 1.15 grams of Polyimide.
FIG. 14 illustrates one set of testing data showing what is deemed acceptable performance in one embodiment.
FIG. 15 shows calculations which illustrate some aspects and advantages associated with the 1.3 gram pre-wet recipe described above over the 3.0 grams required for acceptable semiconductor performance/yield in the absence of Polyimide solvent pre-wetting.